Scalable handling of real arithmetic is a crucial part of the verification of hybrid systems, mathematical algorithms, and
mixed analog/digital circuits. Despite substantial advances in verification technology, complexity issues with classical decision
procedures are still a major obstacle for formal verification of real-world applications, e.g., in automotive and avionic
industries. To identify strengths and weaknesses, we examine state of the art symbolic techniques and implementations for
the universal fragment of real-closed fields: approaches based on quantifier elimination, Gröbner Bases, and semidefinite
programming for the Positivstellensatz. Within a uniform context of the verification tool KeYmaera, we compare these approaches
qualitatively and quantitatively on verification benchmarks from hybrid systems, textbook algorithms, and on geometric problems.
Finally, we introduce a new decision procedure combining Gröbner Bases and semidefinite programming for the real Nullstellensatz
that outperforms the individual approaches on an interesting set of problems.
Keywords Real-closed fields - decision procedures - hybrid systems - software verification